Still over boosting

[2gtalonman]

I installed a gauge and a BC I have it almost all the way set "out" for no boost and im still peaking 18-20 psi even with it fully adjusted out, and i know the BC works i had it on my galant, little help please?? what could cause this...

I keep hitting fuel cut.

I have hard IC pipeing both

bigger j-pipe

2.5 turbo back


thats all thanks..

 

[Avionixx]

Remove the BC and hook up the wastegate directly to a boost source and see if you're still over boosting. If not, then you either have an issue with the boost source (vacuum line blocked or has a leak, doesn't actually see boost, etc) or the MBC is not working properly.

 

[qiklitltsi]

I had the same problem when I put on a new turbo, It was because the ball in the bc would move and block the hole completly. I had to get a diffrent bc to correct the problem.

 

[STM tuned]

boost creep?

 

[2gtalonman]

it does creep it stays at 10psi for like 2k of the rpm's, then all hell breaks out, the BC like i said IS good came right off a working car, I hooked the j-pipe right to the acuator and its doing the same thing.

 

[Avionixx]

Then your actuator is probably damaged. If you have a Mityvac you can try applying vacuum to it and see if it holds; if it leaks out immediately, then you need a new actuator.

 

[2gtalonman]

Where could i buy a midivac?? is there a write up on how to do it? thanks.

 

[Avionixx]

They should sell them at automotive related stores, here's what it looks like:

Mityvac

Basically just hook it up to the wastegate actuator and apply vacuum. It should hold pretty much indefinitely. I know boost isn't vacuum, but if it won't hold vacuum then you can be sure it won't hold boost.

 

[2gtalonman]

Very good point, thank you.

 

[viprez586]

If your actuator checks out good, it could be the flapper not opening enough, some minor porting could help depending how much boost you plan on running, or while you have it out get the 34mm flapper and do some extra porting for increased boost control.